The steam reforming of hydrocarbons, such as methane, ethane, propane, butanes, light naphtha, and the like, is most often accomplished in externally heated tubes which contain catalyst. The product of such process is a synthesis gas composed primarily of H2 and CO. This type of process is known in the art, and is regularly practiced at industrial scale. In general, a hydrocarbon and steam mixture in the proper proportion is introduced into a reformer furnace, containing a plurality of parallel tubes packed with a suitable reforming catalyst. The tubes are externally heated to provide the endothermic heat of reaction for the reforming process, with the reaction generally being effected at a temperature above 1600 degrees F.
The above process has numerous limitations, especially that of effecting economic heat transfer through the tubes at the high temperatures and high heat fluxes employed in the steam reforming process. For example, in order to withstand the high temperatures used in steam reforming, expensive heat resistant alloys must be used in constructing the furnace, thereby raising capital costs. Moreover, carbon deposition on the catalyst necessitates the use of excess amounts of steam in the hydrocarbon and steam mixture, which serves to decrease the net conversion efficiency and results in a high ratio of H2 to CO in the synthesis gas product when a 1:1 ratio is optimum for synthesis of some high-value products, including the production of mixed-alcohols. Furthermore, when CO2 is present in the hydrocarbon and steam mixture and CO2 is intended to participate in the reforming reactions, the deposition of carbon on the catalyst becomes more problematic and the catalyst is thereby deactivated.
Therefore, it would be advantageous to develop an improved process for reforming of hydrocarbons.
As such, it would be desirable to provide processes and systems which allow for improved steam reforming. Additionally, it would be desirable to provide processes and systems which allow for reduced cost materials.